Ok well I was given a Marine Batt. and I know the basics of the wiring for dual batt. use for car audio. But I would like to get a refresh on certain things to be 100%. I know it goes main batt - fuse(amp rating) - isolater relay - fuse(amp rating) - second batt. - fuse(amp rating) - Cap's - Amp and this is based off my setup. Now for the Isolater Relay, I have a 90amp Alternator, what type of Relay amps should I look for to keep a good charge 100 150 200 for a 13V Deep cycle batt?